Identification of the Toxic Pentapeptide Nodularin in A
Total Page：16
File Type：pdf, Size：1020Kb
A tica nal eu yt c ic a a m A r a c t h a P Pacheco et al., Pharm Anal Acta 2016, 7:5 Pharmaceutica Analytica Acta DOI: 10.4172/2153-2435.1000479 ISSN: 2153-2435 Research Article Open Access Identification of the Toxic Pentapeptide Nodularin in a Cyanobacterial Bloom in a Shrimp Farm in South American Atlantic Coast Pacheco LA1,3, Kunrath N1, Costa CM1,4, Costa LDF1, Foes GK2, Wasielesky W2 and Yunes JS1* 1Laboratory of Cyanobacteria and Phycotoxins, Institute of Oceanography, Federal University of Rio Grande, RS, Brazil 2Aquaculture Marine Station (EMA), Institute of Oceanography, Federal University of Rio Grande, RS, Brazil 3Post Graduate Program in Physical, Chemical and Geological Oceanography , Institute of Oceanography, Federal University of Rio Grande, RS, Brazil 4Post Graduate Program in Aquaculture, Institute of Oceanography, Federal University of Rio Grande, RS, Brazil *Corresponding author: Yunes JS, Laboratório de Cianobactérias e Ficotoxinas, IOFURG, Universidade Federal do Rio Grande, 96.203-270 - Rio Grande, RS, Brazil, Tel: +55 53 32336737; E-mail: [email protected] Received date: Apr 28, 2016; Accepted date: May 23, 2016; Published date: May 25, 2016 Copyright: © 2016 Pacheco LA et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Since 2010, blooms of the brackish cyanobacteria Nodularia spumigena are recurrent in the shrimp growth tanks of the Marine Aquaculture Station during summer in Southern Brazil. Cyanobacterial growth led to a decrease in the white shrimp Litopenaeus vannamei productivity. In the summer of 2014, a Nodularia bloom was collected from the tanks; filaments were separated by flotation and washed thoroughly twice in F/2 culture medium. Healthy filaments were lyophilized and the powder used for nodularin quantification by HPLC-DAD and immunoassays. Nodularin containing lyophilized powder was also tested for toxicity against the brine shrimp Artemia salina post-larvae and the white shrimp Litopenaeus vannamei 35 days old larvae. The lyophilized Nodularia powder contained 1.88 mg of the toxin nodularin g-1d.w. Its toxicity was confirmed in bioassays with Artemia salina and Litopenaeus vannamei giving -1 a LC50 of 1.22 and 2.50 µgL of nodularin, respectively. This paper firstly describes the occurrence and the toxicity of nodularin in South Atlantic coastal waters with consequences to shrimp farming. Keywords Cyanobacteria; Litopenaeus vannamei; Nodularia Later, dog and cattle poison have also resulted from nodularin spumigena; Nodularin; Shrimp farm; Toxicity tests ingestion in the Baltic Sea [3,4], and more specifically in the gulf of Finland, considerable losses in the North Atlantic flounder Platichtlys Introduction flexus populations were documented following a Nodularia bloom collapse [2]. Nodularia cells produce the pentapeptide nodularin Early registration of scum, or colored waters, consistent with whose toxicity and lethal concentration (i.p.) in mammals are similar cyanobacterial blooms refer back to at least 1853. In a perceptive and to microcystins [5,6]. The main target organ of nodularin and prescient paper in Nature, the Adelaide assayer and chemist George potentially MC-LR is the liver [7], which expresses high levels of many Francis reported on stock deaths at Milang on the shores of Lake uptake transporters, including Oatps [8]. One of the important Alexandrina in South Australia. Francis attributed the deaths to the molecular toxicological mechanisms of these toxins is the inhibition of ingestion and toxicity of scums of the cyanobacterium Nodularia serine/threonine specific protein phosphatases PP1 and PP2A [9]. This spumigena [1]. in turn leads to hyperphosphorylation of proteins, ultimately resulting in deterioration of cellular integrity. A marine shrimp farm located on the south coast of Brazil (Cassino Beach, RS, Brazil) uses the "bioflocs" system of intensive cultivation, in order to achieve a high production of shrimp associated with high air flow with this microbial aggregate and without water exchange [10]. The microbial aggregation was stimulated by the extra addition of organic carbon sources; however, at outdoors shrimp tank systems this carbon input stimulates photoautotrophic organisms. Moreover, shrimp excrements and excess food portions, under sunlight exposure (open systems), led to a microbial growth [11]. Due to its geographical location the Aquiculture Marine Station (EMA) from the Federal University of Rio Grande (32º12’S, 52º10’W) runs the intensive shrimp (Litopenaeus vannamei) growth mainly at the end of spring and before autumn. In this period high illumination Figure 1: Open shrimp tanks next to the shoreline at the Cassino and drought turns environmental conditions ideal for the shrimp beach where EMA is located. Intense blue-green color of growth. On the other hand, these were also ideal conditions for cyanobacterial blooms in the water. cyanobacterial (Nodularia spumigena) growth leading to a decrease on shrimp growth and survival in some outdoors tanks. Pharm Anal Acta, an open access journal Volume 7 • Issue 5 • 1000479 ISSN: 2153-2435 Citation: Pacheco LA, Kunrath N, Costa CM, Costa LDF, Foes GK, Wasielesky W and Yunes JS (2016) Identification of the Toxic Pentapeptide Nodularin in a Cyanobacterial Bloom in a Shrimp Farm in South American Atlantic Coast. Pharm Anal Acta 7: 479. doi: 10.4172/2153-2435.1000479 Page 2 of 3 The presence of Nodularia filaments in the outdoor tanks was first 5.41.240 software. The analytical column used for analysis was a Luna identified and reported by Costa et al.[12] in the period above C18 (2), (250 x 4.6 mm, 5 μ) (Phenomenex®). The detection limit, described with the strong fall in productivity described in Table 1. resulting from SIGMA-Aldrich® standard analyzed by HPLC-DAD for nodularin was 0.025 µg L-1. Elisa analysis for NOD was also done using -1 PRODUCTIVITY (kg ha ) the specific immunoassay test for nodularins in the range from: 0.25 to -1 YEAR TANKS TANKS with NOD 1 μg L (Beacon® (ME, USA)) following instructions of the supplier. 2010 13600 7100 Toxicity tests 2011 5630 2200 NOD containing lyophilized powder was used in the toxicity assays against larvae of the brine shrimp Artemia salina and the 35 days old Table 1: Productivity of the white shrimp Litopenaeus vannamei in the post-larvae of the white shrimp Litopenaeus vannamei. Both tanks with, and without, Nodularia (NOD) blooms. organisms were supplied by the Marine Aquaculture Station (EMA- FURG). Both tests were run without water renovation, but with a strict However the precise estimation and identification of the toxin control of the nodularin contents in all triplicates during 24 h and 92 h content and toxicity to shrimps is necessary and this is the objective of length experiments, respectively. Thus, the NOD containing the present work. The present work also described and summarized lyophilized powder was used in tests at seven concentrations ranging methodological procedures which can be followed to monitor the from 0 to 5.0 mg powder per mL-1 in a 500 mL glass bottle with occurrence of this toxic pentapeptide in aquaculture farms. aeration for white shrimp Litopeaneus vannamei. The NOD containing lyophilized powder was also used in seven concentration tests ranging -1 Materials and Methods from 0 to 5.0 mg. mL for the brine shrimp Artemia salina in a 1 mL well of a 96 wells plate kept inside a 28oC incubation chamber. Cyanobacterial sampling Results The bloom analysed in this work occurred in the tank number 3 during the south hemisphere summer from 2013 to 2014. Samples Nodularin identification were collected using buckets and taken to the laboratory as a total volume of 10 liters. Floating filaments of Nodularia were separated Lyophilized powder from bloom in the tanks was used for from the water, algae and other organisms by the use of a slow identification of the presence of nodularin in the samples. Analysis by centrifugation LKB centrifuge at 2.000 rpm and separating a 2 liters High Performance Liquid Chromatography attached to a UV-DAD sample each time. Floating healthy filaments were predominant and detector after methanol extraction, and concentration, reveals the were pipeted into a 50µm phytoplankton net and fully washed 3 times presence of a single peak. A single peak was detected at a retention with the F/2 culture media prepared to marine cyanobacteria salinity. time from 6.1 to 6.3 minutes which corresponds to an identical peak of The resulting scum achieved 100% purity of Nodularia cells. The scum the nodularin standards supplied by Sigma-Aldrich® (Figure 2) or was frozen and totally transferred to a lyophilizer (Micromodulyo- Alexis Biochemicals®. Edwards®). Sample treatment of nodularin analysis A 500mg of Nodularia lyophilized powder was weighted in a precision balance (Marte, Brazil). A 7 mL of Milli-Q water plus 8mL of methanol were added to it and let to extract during 24 h on an orbital shaker (Aros 16O, Thermolyne-USA®) at room temperature. The whole extract was transferred to a rotaevaporator and let to concentrate during 1 hour. The resulting sample was homogenized using an ultrasonic device (Hielsher, Germany®) three times during 30 seconds, with 30 seconds intervals. This sample final volume was collected into a glass cylinder and set to 6 mL, with the initial mixture of Milli-Q water:methanol (7:8). This extract was used and applied to the NOD concentration analysis by HPLC-DAD and immunoassays for microcystins and nodularins. The preparation of the solutions to HPLC-DAD was performed using only the reagents with HPLC grade and ultrapure Milli-Q water in preparing solutions. NOD standards and their reference material certificates were obtained from SIGMA-Aldrich® and from Abraxis® Figure 2: Chromatograms of the NOD bloom sample (a) and the (USA).